Existing compressors, such as air conditioning compressors found in vehicles, are relatively noisy. In normal use, a fluid such as a refrigerant gas enters the compressor via a suction chamber in the rear housing of the compressor. The fluid then proceeds through the cylinder block and its chambers where it is drawn into and exited by reciprocating piston movement, which compresses the fluid and discharges it out of the pump. The discharge fluid exits the compressor via a discharge chamber also located in the rear housing and positioned adjacent the suction chamber. Compression of the fluid via the series of reciprocating pistons results in large pressure pulsations and fluctuations, which in turn result in the generation of noise, vibration and harshness (NVH).
Many compressors include built-in flow noise control devices, such as a muffler. Unfortunately, these devices are usually a bulky addition to the compressor casting or housing, increasing the overall size and mass of the compressor significantly. Other drawbacks include a large flow loss due to the structure of the channels linking the muffler and compressor.
Accordingly, there exists a need to provide a compressor and rear housing which reduces NVH without increasing the overall size of the compressor or inducing flow loss.